A Shape‐Adaptable Organometallic Supramolecular Coordination Cage for the Encapsulation of Fullerenes

The development of three‐dimensional supramolecular coordination complexes (SCCs), with cavities suitable for guest binding, is of great interest because these materials are useful in a large number of applications. Herein, a nickel‐conjoined organometallic molecular prism is described, which has been fully characterized. The X‐ray diffraction structure of the molecule reveals that the cage possesses an internal cavity with a volume of 1028 Å 3 , thus suitable for the encapsulation of large 3D‐molecules, such as fullerenes. This cage shows highly selective complexation of C 70 over C 60 , thus being potentially useful for fullerene separation and purification. The combined experimental and computational studies suggest that the complexation process is largely entropically‐driven, and DFT calculations suggest that the cage is flexible and can adapt the size and the shape of the cavity to maximize the face‐to‐face interaction with the fullerenes.